Heat exchanger

Abstract: The invention relates to a heat exchanger of the type which is constructed from a number of heat exchanger elements (1) consisting of a tubular jacket (2) with thermal transfer tubes (3) lying within the jacket. The heat exchanger elements (1) are joined together to form a heat exchanger, in that each end of a heat exchanger element is provided with a modular unit (4) which constitutes the frame of the heat exchanger. A jacket connection (5) is connected to each two modular units (4) and constitutes an extension of the tubular jacket (2). The jacket connection (5) is designed as an H pipe.

Description: TECHNICAL FIELD The present invention relates to a heat exchanger according to the preamble of claim 1. BACKGROUND ART Heat exchangers, of which there are numerous types, are employed to heat or cool a liquid product. Using, for example, steam or water at different temperatures, it is possible to heat or cool a product, which is preferably liquiform, to the desired level. Heat exchangers are put into use within various process industries and are also common occurrences within food industries such as, for example, dairies. One well-known type of heat exchanger is the so-called tube heat exchanger which consists of one or more heat exchanger elements which are interconnected into a flow system. The heat exchanger elements include one or more thermal transfer tubes surrounded by an outer tubular jacket. The thermal transfer tubes are interconnected to form a product flow insert which, in turn, is interconnected by means of product elbow pipes so as to circulate the product which is to be heated or cooled depending upon the process for which the heat exchanger is employed. The thermal transfer tubes lie enclosed in a tubular jacket that surrounds the thermal transfer medium which may consist of water at different temperatures, steam or other types of liquids or gases. A heat exchanger of the kind indicated in the preamble of claim 1 is known from US-A-710 810 or US-A-1 037 798 where the tubular jackets are connected with each other by coupling pieces which support the tubular jackets as well as the transfer tubes. The elbow pipe, which is attached to the coupling piece, as well as the coupling pieces are secured to each other by bolts and flanges. US-A-710 810 shows an assembly where the coupling pieces of pairs of tubular jackets can be bolted to each other linearly in order to be able to assemble heat exchangers of different sizes. These types of heat exchanger are, however, complex and expensive to produce. It requires exact fit of connections, at the same time as demanding a certain degree of play on being mounted in a frame, since the tubes in the heat exchangers are subjected to thermal expansion which may give rise to extreme inner stresses in both tubes and frame. Therefore, a stiff and supporting frame is necessary in order to assemble large heat exchangers. Moreover, the replacement of gaskets and other spare parts is difficult and requires lots of time to remove bolts, flanges and other connecting parts. Additionally, there is no possibility to connect heat exchanger elements in other directions than linearly next to each other without additional pipes and connections. It has previously proved difficult to produce a modular version of a heat exchanger of the tube type, since each heat exchanger requires its own individual design. A tube heat exchanger of traditional type is complex to assemble and, on replacement of spare parts, extensive dismantling is often required for replacing individual parts. OBJECTS OF THE INVENTION One object of the present invention is to join together the elements included in the heat exchanger such that the heat exchanger will be simple to assemble and such that those parts which constitute the heat exchanger will be easy to standardize and modularize in that a small number of parts of which the heat exchanger consists constitutes both the frame and connection conduits for product flow and thermal transfer medium. A further object of the present invention is to realize a simplified and more economical design and construction, which entails fewer spare parts and which obviates the problems inherent in the replacement of individual spare parts in a previously assembled heat exchanger. SOLUTION These and other objects have been attained according to the present invention by the features of claim 1. Preferred embodiments of the present invention have further been given the features of the appended dependent claims. BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS One preferred embodiment of the present invention will now be described in greater detail hereinbelow, with particular reference to the accompanying Drawings, in which: Fig. 1 is a schematic overview of a portion of a heat exchanger according to the present invention, partly as an exploded view; Fig. 2 is a plan view of a part of a heat exchanger, partly in section; Fig. 3 shows a section taken along the line A-A in Fig.2 Fig. 4 shows an end elevation of a part of a heat exchanger; Fig. 5 is a plan view of a modular unit; Fig. 6 shows a section taken along the line B-B in Fig. 4; Fig. 7 is a plan view of a jacket connection, partly in section; Fig. 8 is a section taken along the line C-C in Fig. 6; Fig. 9 is a plan view of half of a jacket connection with inlet or outlet connection; Fig. 10 is a plan view of a number of interconnected modular units; Fig. 11 shows a connection profile; Fig. 12 shows an end elevation of an assembled heat exchanger; Fig. 13 shows the other end elevation of the same assembled heat exchanger; and Fig. 14 is a schematic presentation of the modular adaptation of the modular units. The Drawings show only those details essential to an understanding of the present invention. DESCRIPTION OF PREFERRED EMBODIMENT Fig. 2 shows a part of a heat exchanger with three heat exchanger elements 1. Each heat exchanger element 1 consists of an outer tubular jacket 2 in which there are disposed a number of thermal transfer tubes 3. A modular unit 4 is fixedly secured at each end of the tubular jacket 2 of the heat exchanger elements 1. A jacket connection 5 is fixedly mounted on two neighboring modular units 4. As a result, the jacket connection 5 will constitute an extension of the tubular jacket 2 and will thereby surround the extension of the thermal transfer tubes 3. At each respective end, the thermal transfer tubes 3 are fixedly welded into a tube plate 22 so that they together constitute a product flow insert. These product flow inserts are interconnected to one another by product elbow pipes 6 or a product connection 19. This product flow insert of conventional type is inserted into the jacket connection 5 against one or more gaskets 7 so that the product flow insert is movable relative {o the tubular jacket 2 and the jacket connection 5. Fig. 3 shows a cross section through Fig. 2, taken along the line A-A, where the thermal transfer tubes 3 are seen as disposed within their tubular jacket 2. The Drawing also shows one end of the jacket connection 5, which is fixedly connected by screw connections to two modular units 4. Fig. 4 shows an end elevation of a part of a heat exchanger with two heat exchanger elements 1 and the outer elbow pipe which constitutes the product elbow pipe 6. The product elbow pipes 6 are kept in place by a flange coupling against the product flow inserts. Figs. 5 and 6 show a modular unit 4. The modular unit 4 may, as in the preferred embodiment, consist of two parts, a flange section 8 which is welded to each end of the tubular jacket 2 and a module piece 9 loosely mounted on the flange section. These two parts 8 and 9 may of course be of one piece construction. The flange section 8 may further constitute an extension of the tubular jacket 2 on which the module piece 9 is mounted. The module piece 9 has screw holes 11 for the connection to the jacket connection 5.-The module piece 9 further displays sliding surfaces 10 which are intended to abut against the sliding surface 10 on the immediately adjacent modular unit 4. The module pieces 9 will hereby constitute the frame of the complete heat exchanger and the sliding surfaces 10 take up the loading of the heat exchanger elements 1 interconnected in the heat exchanger. At the same time, the sliding surfaces 10 allow the heat exchanger elements 1 to move towards one another and thus compensate for the thermal action to which the heat exchanger elements 1 are subjected. In those cases when use is made of extremely long heat exchanger elements, of the order of up to 6 meters, one module piece 9 may be employed for supporting the heat exchanger elements 1 in their central region. Figs. 7 and 8 show a jacket connection 5 which substantially consists of an H pipe with two parallel pipe branches, two tubular elements 12 and a connecting element 13 extending at right angles and communicating between these tubular elements 12. The inner diameter of the tubular elements 12 is approximately 0-10 per cent greater than the inner diameter of the tubular jacket 2 of the heat exchanger element 1, which assists in reducing the flow resistance in the thermal transfer medium when this passes through the jacket connection 5. Reduced flow resistance contributes in being able to reduce the capacity of those pumps which are connected to the heat exchanger. One end of the two tubular elements 12 is screwed in place against the module piece on two neighboring modular units 4. Once a product flow insert with its thermal transfer tubes has been inserted into the tubular jacket 2 and jacket connection 5, the product flow inserts will be interconnected with a product elbow pipe 6 or a product connection 19 on inflow or outflow of product to or from the heat exchanger. Fig. 9 shows a jacket connection 14 which constitutes only half of the H jacket connection as described above. This jacket connection 14 is employed on inflow or outflow of the thermal transfer medium. An elbow pipe 16 is connected to the open pipe socket 15 which is hereby formed for inlet or outlet of thermal transfer medium. Fig. 10 shows four mutually adjacent modular units 4 which, in their common corner, are joined together by a coupling profile 17. The appearance of the coupling profile 17 may be varied but substantially consists of a cruciform profile which is loosely inserted into the module piece 9 on the modular unit 4 so that the coupling profile 17 configurationally stable engages with the grooves of the module piece 9. The coupling profile 17 is locked in its one end, in that it abuts against the screw connection between the modular units 4 and the jacket connection 5. The substantially cruciform coupling profile 17 may be made of metal, preferably stainless steel, but it may also be manufactured from polymers or ceramics. Because of their design, the modular units 4 will constitute an almost homogeneous wall in a heat exchanger, and this almost homogeneous wall is intended to prevent the occurrence of the inherent convection which may occur within the heat exchanger because of temperature differences in the various parts of the heat exchanger. In those cases when use is made of a module piece 9 for supporting the central region of a long heat exchanger element 1, this module piece 9 is not entirely homogenous, but ventilation may occur between the different sections. In this case, the module piece 9 thus solely serves a supporting function. Figs. 12 and 13 show the two different side sections of a combined heat exchanger. By supplying product at different points in the heat exchanger and leading off the-product through selected parts of the heat exchanger, and by introducing the thermal transfer medium at other points and leading off this medium therefrom, a coordinated unit will be created, of which the Drawings show but a single example. In those jacket connections 14 which are employed here according to the embodiment illustrated in Fig. 8, i.e. in inflow or outflow of thermal transfer medium, that elbow pipe 16 which constitutes the inlet or outlet conduit will occupy one modular place in the heat exchanger. Since this modular place then lacks a the heat exchanger element 1, a support corresponding to one modular unit 4 must be employed at this modular place. In such instance, use is made of a module piece 18 without the holes which are intended for tubular jacket 2 and thermal transfer tubes 3; This is necessary so as to provide the robustness and stability which are required to be able to build a complex heat exchanger. Figs. 12 and 13 also show how the finished, combined heat exchanger is provided on all sides with cover plates 20 which, in the Drawings, have been made gently arched so as thereby to increase the rigidity in the plate. The cover plates 20 are suitably secured in the module pieces 9. Cover plates 20 are employed when the heat exchanger elements reach elevated temperatures in relation to their ambient surroundings. The entire heat exchanger is mounted on a floor frame 21 for raising up the heat exchanger from the floor. Fig. 14 shows how the modular units 4 may be included in a standardization scheme so that one modular dimension M may encompass two, three, four or six module pieces depending upon the size and type of the heat exchanger element 1 which is employed. A heat exchanger of the above-described type is easier to assemble than conventional tube heat exchangers. Furthermore, replacement of O gaskets and other spare parts is facilitated in that those parts of the heat exchanger which are located above that point where it is intended to replace spare parts need not be dismantled on spare part replacement. The only parts which need to be backed-off and loosened are a product elbow pipe and a jacket connection. This makes a major contribution in reducing the costs for assembly and maintenance of the heat exchanger. As will have been apparent from the foregoing description, the present invention realizes a heat exchanger which may, to a considerable extent, be standardized and modularized and whose units may be combined to form a single complete unit which is more compact and simpler to manufacture, assemble and modify than conventional tube heat exchangers.

Claims: A heat exchanger comprising a plurality of neighbouring heat exchanger elements (1) being interconnected in a flow system, with a product flow and a flow for a thermal transfer medium, each heat exchanger element (1) displaying one or more transfer tubes (3) interconnected to form a flow insert which are surrounded by a tubular jacket (2), further comprising jacket connections (5), each jacket connection (5) constituting an extension of two adjacent tubular jackets (2) and comprising two tubular elements (12), communicating with two tubular jackets (2), and connecting elements (13), interconnecting said connecting elements (12) and elbow pipes (6) connecting said transfer tubes (3) of two heat exchanger elements (1), characterized in that, each tubular jacket (2) is connected to one or more separate modular units (4), said jacket connection (5) is connected to two neighbouring modular units (4), being connected to the ends of said tubular jackets (2), said modular units (4) are movably securable to each other to constitute the frame of the complete heat exchanger and said modular units (4) are disposed to support said heat exchanger elements (1). The heat exchanger as claimed in claim 1, characterized in that said modular unit (4) comprises a flange section (8) being connected to said tubular jacket (2) and a module piece (9) being connected to said jacket connection (5). The heat exchanger as claimed in claim 2, characterized in that said flange section (8) is an extension of said tubular jacket (2) on which said module piece (9) is mounted. The heat exchanger as claimed in claim 2, characterized in that said flange section (8) and said module piece (9) are one piece. The heat exchanger as claimed in one of the claims 2-4, characterized in that said module piece (9) displays sliding surfaces (10) abuting against the sliding surfaces (10) of adjacent modular units (4). The heat exchanger as claimed in one of the preceeding claims, characterized in that said modular units (4) are movably secured in relation to one another by means of a coupling profile (17). The heat exchanger as claimed in claim 6, characterized in that the coupling profile (17) is substantially cruciform and configurationally stably but flexibly engages in four mutually adjacent modular units (4). The heat exchanger as claimed in claims 6 or 7, characterized in that said coupling profile (17) is made of stainless steel. The heat exchanger as claimed in one of the preceeding claims, characterized in that said jacket connection (5) constitutes an H pipe with two parallel tubular elements (12) and at a right angle to the tubular elements (12) a connecting element (13). The heat exchanger as claimed in one of the preceeding claims, characterized in that inlet or outlet for thermal transfer medium is effected via a semi cutoff jacket connection (14) and an inlet or outlet elbow pipe (16).

Inventors: SJOESTROEM ANDERS, SJOESTROEM, ANDERS, Sjöström, Anders
Applicants: TETRA LAVAL HOLDINGS & FINANCE, TETRA LAVAL HOLDINGS & FINANCE SA
Application year: 1994
Main classification: F28F9
IPC codes: F28F9, F28D7